1. Field of the Invention
The present invention is an improved system for generating string ensemble sounds in an electronic musical instrument, specifically an electronic organ. In playing the electronic organ it is often desirable to simulate the sound generated by a multiplicity of stringed instruments, as in a string ensemble. It is difficult to artificially simulate the sound of a string ensemble because: (a) when a stringed instrument is played it produces a complex sound waveform comprising a fundamental frequency and several additional harmonics which are multiples of that fundamental frequency; (b) when several stringed instruments are played together in an ensemble each instrument generates a sound waveform which is slightly out of phase with that of the accompanying instruments since each musician plays at a slightly different time and/or speed even when each musician is playing the same note; and (c) the sound produced by each instrument reaches the listener at a slightly different time due to the different spacial relationship between the listener and each instrument. Accordingly, the fundamental and harmonic waveforms generated by each stringed instrument interact with the waveforms produced by the accompanying string instruments to acoustically cancel and reinforce one another resulting in the distinctive sound characteristics of a string ensemble. This acoustic phenomenon is particularly noticeable to the listener due to the directional nature of the predominately high frequency sounds produced by a string ensemble.
2. Description of the Prior Art
The prior art recognizes the need for providing an electronic organ with means for producing string ensemble sounds. In some prior art electronic organs string ensemble sounds are simulated by use of multiple channel amplifier and speaker systems. The independent production of sound through each channel of such system results in the acoustical cancellation and reinforcement characteristic of a good string ensemble sound. The cost of the additional components and the cost associated with the manufacture and production of such multiple channel systems, however, can be substantial and frequently results in the organ manufacturer providing a string ensemble feature on only the more expensive organ models.
Less expensive electronic organs of the prior art employ a single channel amplifier circuit and a single speaker system. These single channel electronic organs attempt to provide a string ensemble effect by electronically mixing separate, modulated input signals. Acoustically, however, such single channel systems do not approach in quality the desirable presence and modulation effects produced by the more expensive multiple channel electronic organs.
It is therefore a general object of this invention to provide a single channel string ensemble sound system for electronic organs which overcomes the disadvantages of the prior art string ensemble sound systems.
Another object of this invention is to provide a single channel string ensemble sound system which is lower in cost than, but comparable in quality to, the prior art multiple channel string ensemble sound systems.
Another object of this invention is to provide a single channel string ensemble sound system for electronic organs which can generate sounds which acoustically cancel and reinforce one another in a manner which results in good string ensemble sound.
Another object of this invention is to provide a single channel string ensemble sound system which receives a signal representing string ensemble sounds, electronically mixes and amplifies the signal and drives two transducers substantially 180.degree. out of phase electronically with the mixed signal with the two transducers being positioned at substantially right angles to each other.
Other objects of this invention will become apparent upon reading the following summary of the invention, the detailed description and appended claims, and upon reference to the accompanying drawings.